Electric power tool
First Claim
1. An electric power tool comprising:
- an electric motor;
a control part configured to control a rotating speed of the electric motor; and
a rotating speed detecting circuit connected to the control part, and configured to detect a rotating speed of the electric motor, whereinthe control part has an automatic mode in which the control part controls the rotating speed of the electric motor on the basis of a load judge value and a no-load judge value,when the control part is in the automatic mode, and the electric motor is at least in a no-load state, the control part carries out a feedback control so that the rotating speed of the electric motor approaches a no-load rotating speed, by controlling a control value that is changing a voltage supplying to the motor,the control part is configured to set the load judge value to be smaller than the no-load judge value,the control part controls the electric motor so that the electric motor is rotated at a no-load rotating speed when the control value of the electric motor is smaller than the no-load judge value, and the control part controls the electric motor so that the electric motor is rotated at a load rotating speed that is larger than the no-load rotating speed when the control value of the electric motor is larger than the load judge value.
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Accused Products
Abstract
An object of the present invention is to provide an electric power tool capable of automatically changing the rotating speed of an electric motor in accordance with operation conditions. The electric power tool 11 which carries out an operation of polishing, peel-off, cutting, or the like by swinging a tip tool 13 attached to a tool retaining 31 part within the range of predetermined angles by the drive power of the electric motor 12, wherein the electric power tool has a control device configured to indirectly detect the load of the tip tool from a current value, and to control the rotating speed of the electric motor 12 to a maximum rotating speed and a minimum rotating speed on the basis of the load of the tip tool 13.
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Citations
13 Claims
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1. An electric power tool comprising:
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an electric motor; a control part configured to control a rotating speed of the electric motor; and a rotating speed detecting circuit connected to the control part, and configured to detect a rotating speed of the electric motor, wherein the control part has an automatic mode in which the control part controls the rotating speed of the electric motor on the basis of a load judge value and a no-load judge value, when the control part is in the automatic mode, and the electric motor is at least in a no-load state, the control part carries out a feedback control so that the rotating speed of the electric motor approaches a no-load rotating speed, by controlling a control value that is changing a voltage supplying to the motor, the control part is configured to set the load judge value to be smaller than the no-load judge value, the control part controls the electric motor so that the electric motor is rotated at a no-load rotating speed when the control value of the electric motor is smaller than the no-load judge value, and the control part controls the electric motor so that the electric motor is rotated at a load rotating speed that is larger than the no-load rotating speed when the control value of the electric motor is larger than the load judge value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An electric power tool comprising:
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an electric motor; a control part configured to control a rotating speed of the electric motor by controlling a control value that is changing a voltage supplying to the motor; and a rotating speed detecting circuit connected to the control part, and configured to detect a rotating speed of the electric motor, wherein the control part has an automatic mode in which the control part changes the rotating speed of the electric motor on the basis of a load judge value and a no-load judge value, wherein the control unit is configured to perform in the automatic mode that; drives the electric motor so that the rotating speed of the electric motor approaches a no-load rotating speed in a no-load state by controlling the control value, drives the electric motor so that the rotating speed of the electric motor approaches a load rotating speed that is larger than the no-load rotating speed in a load state by controlling the control value, increasing the control value and drives the electric motor at the load rotating speed when the control value changed by the control unit in accordance with increasing in a load on the electric motor exceeds the load judge value in the no-load state, reducing the control value and drives the electric motor at the no-load rotating speed, when the control value changed by the control unit in accordance with decreasing in the load on the electric motor becomes smaller than the no-load judge value in the no-load state, and wherein the no-load judge value is larger than the load judge value.
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Specification